Rifles such as but not limited to the AR15 utilize impingement systems to cycle the bolt carrier during the firing process. As is known in the art, there are two types of impingement systems. A direct gas impingement system is operably coupled to the barrel of the rifle and includes a port that is operably coupled to the barrel chamber and a gas tube adjacent to the barrel. A portion of the gas created during the firing of a round escapes into the port and is routed back to the bolt carrier, which facilitates the rearward movement thereof. The alternative style of impingement system is a gas piston impingement system. The gas piston impingement system also includes a port that is operably coupled to the barrel but leads to a piston chamber. The piston chamber contains a piston head wherein the piston head includes a piston rod extending therefrom having an end adjacent to the bolt carrier. During the firing process a portion of the gas is directed from the barrel and into the piston chamber which drives the piston rod rearward towards the bolt carrier in order to facilitate the movement thereof.
One problem with the current impingement systems mentioned herein is the continuous introduction of carbon-laden gas into either the gas tube and firing chamber or the piston chamber. As rounds are fired the accumulation of carbon and other contaminants build up in various areas of the firearm and reduce the effectiveness of its components. Without regular cleaning this can lead to the misfiring or jamming of the rifle during the shooting process.
Another problem with existing impingement systems is there lack of gas control. Both existing types of impingement systems utilize a method of controlling the gas flow from the barrel into the port that controls the input flow of gas into the gas block port of the impingement block. Utilization of this technique results in excess pressure on the impingement system block and excessive heat build-up. This technique further causes flow blow-back into the barrel and thus creating a need for more frequent cleaning of the barrel. This increases the wear on the component and ultimately leads to the early failure thereof.
Accordingly, there is a need for an impingement system for a firearm that is operable to control the gas flow into the impingement block so as to eliminate contaminant build-up in other areas of the firearm and reduce the heating of the impingement block so as to improve the overall performance of the firearm. Additionally, it is desired to have an impingement gas block that utilizes an adjustable gas flow control member that provides stepped control feedback to the user so as to more precisely calibrate the adjustable gas flow control member.